The present invention relates generally to sensors and fabrication methods, and more particularly, to micromachined acoustic sensors for monitoring electrochemical deposition, methods for fabricating micromachined acoustic sensors, and methods for in-situ monitoring of electrochemical deposition processes using such sensors.
As microsystem feature sizes continue to shrink, the level of integration and complexity of microelectronic devices continues to increase. Microsystems packaging must also evolve to accommodate these trends in integrated circuit (IC) technology. Packaging requirements, such as cost, power, input/output (I/O) count, and operating frequency, for example, must be consistent with IC roadmap projections. Moreover, manufacturing challenges also increase as feature sizes decrease. Improvements in fabrication methods and processes are critical if inexpensive and reliable devices with such small dimensions are to be produced. Semiconductor manufacturing processes require hundreds of successive processing steps, and each of these can potentially contribute to yield loss and increased cost. Therefore, manufacturing technology development requires not only advancement in fabrication processes, but also advances in process monitoring and control.
Effective process control can be provided by in-situ monitoring, process modeling, and real-time, closed-looped operation. In-situ monitoring employs sensors to measure and monitor critical manufacturing process parameters in real time, thus permitting early detection of defective components and process shifts. There is a shortage of sensors that have been developed as in-situ process monitors, however. Many current methods utilize optical techniques to monitor various process parameters. These methods rely on “looking” at a process to monitor its status. While these methods are relatively common for in-situ process monitoring, the equipment they employ can be expensive and can have equipment mounting and calibration challenges.
It would be desirable to have inexpensive and reliable sensors for monitoring electrochemical deposition, methods of fabricating such sensors and methods for in-situ monitoring of electrochemical deposition processes using such sensors.